CN112246637A

CN112246637A - Grit multi-stage screening device

Info

Publication number: CN112246637A
Application number: CN202011005461.XA
Authority: CN
Inventors: 周汝宝; 米志勇; 屠积
Original assignee: Gaoyou Schindler Construction Machinery Group Co ltd
Current assignee: Gaoyou Schindler Construction Machinery Group Co ltd
Priority date: 2020-09-22
Filing date: 2020-09-22
Publication date: 2021-01-22

Abstract

The invention relates to a multi-stage sand and stone screening device which comprises a base, a support rod, a cross rod, a conveying mechanism and a screening mechanism, the supporting rod is arranged at one end of the base, the cross rod is arranged above the base through the supporting rod, the conveying mechanism is arranged at one end of the base far away from the supporting rod, the screening mechanism is arranged at one side of the fixing plate far away from the supporting rod, the multi-stage sand and stone screening device realizes feeding through the conveying mechanism and multi-stage sand and stone screening through the screening mechanism, compared with the existing screening device, the device has the advantages that through one output end, the operation of the transmission mechanism and the screening mechanism can be realized, the energy is saved, the online screening of the sandstone is realized through the linkage of the transmission mechanism and the screening mechanism, meanwhile, the linkage adopts a pure mechanical structure, so that the use of electronic elements such as a sensor and the like is avoided, the stability of the device is improved, and the service life of the device is prolonged.

Description

Grit multi-stage screening device

Technical Field

The invention relates to a multi-stage sand and stone screening device.

Background

The screening machine utilizes the relative motion of bulk materials and a screen surface to enable partial particles to penetrate through screen holes, and divides materials such as sand, gravel, broken stone and the like into vibration screening mechanical equipment with different grades according to the particle size, the screened particle grade depends on the screen surface, the screen surface is divided into three types of grates, plate screens and mesh screens, the screening machine is divided into rolling screening and vibration screening according to the principle, the rolling screening comprises a screen shaft type screening machine, a drum screen, a solid spiral roller screen, a blade type roller screen and the like, and the vibration screening basically comprises a banana screen, a high-clothes screen, a relaxation screen and the like.

Traditional screening plant is generally through the manpower use the spade to fall the sieve on the screen cloth, thereby sieve, this kind of mode consumes great manpower, and efficiency is not high, automatic screening plant has consequently appeared on the market, and current automatic screening plant generally can only once sieve the grit, when the more even grit of needs granule, the screen cloth that will use different apertures carries out a lot of screening, the operation is comparatively troublesome, and current automatic screening plant generally all needs a plurality of driving sources difference drive arrangement to convey and sieve, energy resource consumption is great.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: in order to overcome the defects of the prior art, the multi-stage sand and stone screening device is provided.

The technical scheme adopted by the invention for solving the technical problems is as follows: a multi-stage sand and stone screening device comprises a base, a support rod, a cross rod, a conveying mechanism and a screening mechanism, wherein the support rod is arranged at one end of the base, the cross rod is arranged above the base through the support rod, the conveying mechanism is arranged at one end, far away from the support rod, of the base, and the screening mechanism is arranged at one side, far away from the support rod, of a fixing plate;

the conveying mechanism comprises a driving assembly and a conveying assembly, the driving assembly comprises a motor and a driving shaft, the motor is horizontally arranged on a base, the driving shaft is installed on the motor, the conveying assembly comprises a connecting unit and a conveying unit, the conveying unit comprises rollers, positioning shafts and a conveying belt, the number of the positioning shafts is two, one positioning shaft is arranged at one end, close to the motor, of the base, the other positioning shaft is arranged above a fixed plate, the number of the rollers is two, the two rollers are respectively sleeved on the two positioning shafts, the two rollers are respectively in key connection with the two positioning shafts, the two rollers are in transmission connection through the conveying belt, the connecting unit comprises two rotating wheels, the two rotating wheels are respectively sleeved on the driving shaft and the positioning shafts, the two rotating wheels are respectively in key connection with the driving shaft and the positioning shafts, and the;

the screening mechanism comprises screening components, a pushing component and a returning component, the screening components comprise fixed plates and screening units, the number of the fixed plates is two, the two fixed plates are uniformly arranged along the axis direction of the supporting rod, the discharge port is arranged on the fixed plates, the number of the screening units is three, the three screening units are respectively arranged on the fixed plates and the base, the screening units comprise screening boxes and screen meshes, the screening boxes are arranged on the fixed plates, the screening boxes are slidably connected with the fixed plates, the bottom of the screening boxes is open, the screen meshes are arranged at the opening parts of the bottom of the screening boxes, the screen meshes are just opposite to the discharge port, the pushing component comprises a rotary disc, a rotary rod, a push plate and a push rod, the rotary disc is arranged on the driving shaft, the rotary disc is fixedly connected with the driving shaft, the rotary disc is coaxially arranged with the driving shaft, and the rotary, the rotary plate comprises a base, a rotary plate, a base, a push plate, a return assembly, a spring, a press rod, a press plate and a support rod, wherein the rotary plate is arranged on the base, the base is provided with a sliding groove, one end of the push plate is positioned in the sliding groove, the push plate is connected with the sliding groove in a sliding manner, one rotary rod is abutted against the push plate, the push rod is arranged on the push plate, the push rod is three, the three push rods are respectively arranged corresponding to the three screening boxes, the push rod is abutted against one end of each screening box, the return assembly comprises three return units, the three return units are respectively arranged corresponding to the three screening boxes, the return assembly comprises a press rod, a press plate and a spring, the press rod penetrates through the support rod, the press rod is connected with the support rod in a sliding manner, the press plate is arranged at one end of the press rod, the other end of the spring is connected with the support rod.

In order to avoid the sand and stone leakage in the moving process of the screening box, a bottom plate is arranged at the opening of the bottom of the screening box, grooves are formed in the two sides of the opening of the screening box, which are located below the screening net, of the bottom plate, the two ends of the bottom plate are respectively located in the two grooves, and the bottom plate is connected with the grooves in a sliding mode.

For carrying out better spacing to the removal of push pedal, the one end that the push pedal is located the spout is equipped with the slider, be equipped with the bar groove in the spout, the slider is located the bar inslot, slider and bar groove sliding connection.

For carrying out better spacing to the removal of push pedal, the slider has two, and two sliders set up the both sides of push pedal respectively, the bar groove has two, and two sliders are located two bar inslots respectively.

In order to better limit the movement of the push plate, the section of the sliding block is dovetail-shaped, and the strip-shaped groove is a dovetail groove.

In order to better limit the movement of the pressing plate, the number of the pressing rods is two, the two pressing rods are respectively arranged on two sides of the pressing plate, the two pressing rods penetrate through the supporting rods, the number of the springs is two, and the two springs are respectively sleeved on the two pressing rods.

For carrying out better spacing to the removal of screening case, screening bottom of the case portion is equipped with the stopper, the stopper has two, and two stoppers set up respectively in the both sides of screening case, be equipped with two spacing grooves on the fixed plate, two stoppers are located two spacing inslots respectively, stopper and spacing groove sliding connection.

In order to reduce friction, a pulley is arranged at one end, located in the limiting groove, of the limiting block, and the pulley is in rolling connection with the limiting groove.

In order to realize better conveying effect, the conveying belt is provided with a plurality of baffles which are uniformly arranged.

In order to reduce friction, one end of the rotating rod, which is far away from the rotating disc, is provided with a roller.

The invention has the beneficial effects that the sand multi-stage screening device realizes feeding through the conveying mechanism and multi-stage screening of sand through the screening mechanism, compared with the existing screening device, the device can realize the operation of the transmission mechanism and the screening mechanism through one output end, thereby saving energy, and realizes on-line screening of sand through the linkage of the conveying mechanism and the screening mechanism, meanwhile, the linkage adopts a pure mechanical structure, thereby avoiding the use of electronic elements such as a sensor and the like, and improving the stability and the service life of the device.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a schematic structural view of a multi-stage sand screening apparatus according to the present invention;

FIG. 2 is a schematic diagram of the structure of the conveying mechanism of the multi-stage sand sieving device;

FIG. 3 is a schematic structural view of a sieving unit of the multi-stage sand sieving apparatus according to the present invention;

FIG. 4 is a schematic view of the connection structure of the push plate and the base of the multi-stage sand sieving device of the present invention;

in the figure: 1. the automatic screening machine comprises a base, a support rod 2, a cross rod 3, a motor 4, a driving shaft 5, a roller 6, a positioning shaft 7, a conveying belt 8, a rotating wheel 9, a fixing plate 10, a screening box 11, a screen 12, a rotating disc 13, a rotating rod 14, a rotating rod 15, a push plate 16, a push rod 17, a pressing rod 18, a pressing plate 19, a spring 20, a bottom plate 21, a sliding block 22, a limiting block 23 and a baffle plate.

Detailed Description

The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic views illustrating only the basic structure of the present invention in a schematic manner, and thus show only the constitution related to the present invention.

As shown in fig. 1, the multi-stage sand-gravel screening device comprises a base 1, a support rod 2, a cross rod 3, a conveying mechanism and a screening mechanism, wherein the support rod 2 is arranged at one end of the base 1, the cross rod 3 is arranged above the base 1 through the support rod 2, the conveying mechanism is arranged at one end, far away from the support rod 2, of the base 1, and the screening mechanism is arranged at one side, far away from the support rod 2, of a fixing plate 10;

when the device uses, fall the grit on transport mechanism, convey the grit through transport mechanism for the grit falls into screening mechanism in, through the screening of screening mechanism realization grit.

As shown in fig. 2, the conveying mechanism comprises a driving assembly and a conveying assembly, the driving assembly comprises a motor 4 and a driving shaft 5, the motor 4 is horizontally arranged on the base 1, the driving shaft 5 is arranged on the motor 4, the conveying assembly comprises a connecting unit and a conveying unit, the conveying unit comprises rollers 6, positioning shafts 7 and a conveying belt 8, the number of the positioning shafts 7 is two, one positioning shaft 7 is arranged at one end of the base 1 close to the motor 4, the other positioning shaft 7 is arranged above the fixing plate 10, the number of the rollers 6 is two, the two rollers 6 are respectively sleeved on the two positioning shafts 7, the two rollers 6 are respectively in key connection with the two positioning shafts 7, the two rollers 6 are in transmission connection through the conveying belt 8, the connecting unit comprises two rotating wheels 9, the two rotating wheels 9 are respectively sleeved on the driving shaft 5 and the positioning shafts 7, the two rotating wheels 9 are respectively in key connection with the driving shaft 5 and, the two rotating wheels 9 are in transmission connection through a belt;

the motor 4 is operated, the motor 4 drives the driving shaft 5 to rotate, the driving shaft 5 drives the rotating wheel 9 connected with the driving shaft 5 to rotate, the rotating wheel 9 drives the other rotating wheel 9 to rotate through the belt, the other rotating wheel 9 drives the positioning shaft 7 connected with the other rotating wheel to rotate, the positioning shaft 7 drives the roller 6 connected with the positioning shaft to rotate, the conveying belt 8 is driven to move through the friction force between the conveying belt 8 and the two rollers 6, and therefore the sand on the conveying belt 8 is moved, and the sand is conveyed.

The gravel falls on the conveyor belt 8, and in the process of rising along with the conveyor belt 8, the gravel is blocked by the baffle 23, so that the gravel is prevented from sliding downwards under the action of gravity, and a better conveying effect is realized.

In order to achieve a better conveying effect, the conveying belt 8 is provided with a plurality of baffles 23, and the baffles 23 are uniformly arranged.

As shown in fig. 3-4, the screening mechanism includes a screening assembly, a pushing assembly and a returning assembly, the screening assembly includes two fixing plates 10 and three screening units, the two fixing plates 10 are uniformly arranged along the axial direction of the supporting rod 2, the fixing plates 10 are provided with discharge ports, the three screening units are respectively disposed on the fixing plates 10 and the base 1, the screening unit includes a screening box 11 and a screen 12, the screening box 11 is disposed on the fixing plates 10, the screening box 11 is slidably connected with the fixing plates 10, the screening box 11 has an opening at the bottom, the screen 12 is disposed at the opening at the bottom of the screening box 11, the screen 12 is disposed opposite to the discharge ports, the pushing assembly includes a rotary disc 13, a rotary rod 14, a push plate 15 and a push rod 16, the rotary disc 13 is disposed on the driving shaft 5, the rotary table 13 is fixedly connected with the driving shaft 5, the rotary table 13 is coaxially arranged with the driving shaft 5, the rotary rods 14 are arranged on the rotary table 13, the rotary rods 14 are two, the two rotary rods 14 are respectively arranged at two sides of the rotary table 13, the base 1 is provided with a sliding groove, one end of the push plate 15 is positioned in the sliding groove, the push plate 15 is slidably connected with the sliding groove, one of the rotary rods 14 abuts against the push plate 15, the push rods 16 are arranged on the push plate 15, the push rods 16 are three, the three push rods 16 are respectively arranged corresponding to the three sieving boxes 11, the push rods 16 abut against one end of the sieving boxes 11, the replying assembly comprises three replying units, the three replying units are respectively arranged corresponding to the three sieving boxes 11, the replying assembly comprises a pressing rod 17, a pressing plate 18 and a spring 19, the pressing rod 17 penetrates through the supporting rod 2, and the pressing rod 17 is slidably, the pressing plate 18 is arranged at one end of the pressing rod 17, the pressing plate 18 is abutted to one end, away from the push rod 16, of the screening box 11, the spring 19 is sleeved on the pressing rod 17, the spring 19 is located between the pressing plate 18 and the supporting rod 2, one end of the spring 19 is connected with the pressing plate 18, and the other end of the spring 19 is connected with the supporting rod 2.

When the screening is needed, three screening boxes 11 are sequentially placed on two fixed plates 10 and a base 1, then a bottom plate 20 at the bottom of the screening box 11 is taken down, sand is conveyed into the screening box 11 at a high position by a conveying mechanism, a driving shaft 5 rotates to drive a rotating rod 14 to rotate, when the rotating rod 14 abuts against the pushing plate 15, the rotating rod 14 drives the pushing plate 15 to move, the pushing plate 15 drives a pushing rod 16 to move, the pushing rod 16 drives the screening box 11 to move towards a pressing plate 18, the screening box 11 drives the pressing plate 18 to move, the pressing plate 18 compresses a spring 19, the restoring force of the spring 19 generates reverse thrust on the pushing plate 15, when the rotating rod 14 does not abut against the pushing plate 15, the pushing plate 15 is not blocked, the spring 19 pushes the pressing plate 18 to move reversely under the restoring force of the spring 19, the pressing plate 18 pushes the screening box 11 to move reversely, so that the left and right reciprocating movement of the screening box 11 is realized, and sand in the screening box 11 is screened by screening, the grit that the granule is less falls in the screening case 11 of next layer, carries out the secondary screening through screen cloth 12 once more, and the grit that the granule is less will fall in the screening case 11 on the base 1, and the screen cloth 12 in the top screening case 11 here is the coarse screen, and the screen cloth 12 in the screening case 11 at middle part is well sieve, and the screen cloth 12 in the screening case 11 of below is the fine screen to carry out layer upon layer screening through the screen cloth 12 of three different apertures, thereby realize the multistage screening of grit.

Here, the push plate 15 moves to drive the slide block 21 to move, and the slide block 21 is located in the dovetail groove, so that the slide block 21 can only move along the axial direction of the dovetail groove, and the movement of the slide block 21 is limited, and the movement of the push plate 15 is better limited.

Here, the pressure plate 18 moves to drive the pressure rod 17 to move, and the pressure rod 17 penetrates through the strut 2, so that the movement of the pressure rod 17 is limited.

Here screening case 11 removes drive stopper 22 and removes, and stopper 22 is located the spacing inslot to remove to stopper 22 carries on spacingly, thereby carries on spacingly to the removal of screening case 11, avoids screening case 11 skew.

After the screening, the grit of different granule can be stayed respectively in each screening case 11, inserts bottom plate 20, and screening case 11 can be taken off promptly retrieves the grit, has avoided the grit to fall on the ground, need use the spade to transport the grit once more for the screening of grit is collected more conveniently.

In order to avoid the leakage of sand and stone in the moving process of the screening box 11, a bottom plate 20 is arranged at an opening at the bottom of the screening box 11, grooves are arranged on two sides of the bottom plate 20, which are positioned below the screen 12, at the opening of the screening box 11, two ends of the bottom plate 20 are respectively positioned in the two grooves, and the bottom plate 20 is in sliding connection with the grooves.

For carrying out better spacing to the removal of push pedal 15, the one end that push pedal 15 is located the spout is equipped with slider 21, be equipped with the bar groove in the spout, slider 21 is located the bar inslot, slider 21 and bar groove sliding connection.

For carrying out better spacing to the removal of push pedal 15, slider 21 has two, and two sliders 21 set up the both sides of push pedal 15 respectively, the bar groove has two, and two sliders 21 are located two bar inslot respectively.

In order to better limit the movement of the push plate 15, the section of the sliding block 21 is dovetail-shaped, and the strip-shaped groove is a dovetail groove.

In order to better limit the movement of the pressure plate 18, the number of the pressure rods 17 is two, the two pressure rods 17 are respectively arranged on two sides of the pressure plate 18, the two pressure rods 17 penetrate through the supporting rod 2, the number of the springs 19 is two, and the two springs 19 are respectively sleeved on the two pressure rods 17.

For carrying out better spacing to the removal of screening case 11, screening case 11 bottom is equipped with stopper 22, stopper 22 has two, and two stoppers 22 set up respectively in the both sides of screening case 11, be equipped with two spacing grooves on the fixed plate 10, two stoppers 22 are located two spacing inslots respectively, stopper 22 and spacing groove sliding connection.

In order to reduce friction, a pulley is arranged at one end of the limiting block 22, which is located in the limiting groove, and the pulley is in rolling connection with the limiting groove.

In order to reduce friction, the end of the rotating rod 14 away from the rotating disc 13 is provided with a roller.

When the device uses, through drive assembly drive linkage unit operation, linkage unit drive transmission unit operation, make grit conveying to sieve in the case 11, it removes to promote the subassembly through the drive assembly drive, it promotes each sieve unit removal to promote the subassembly, realize the reciprocating motion of sieving the unit through replying the subassembly, thereby make the grit in the sieve case 11 produce the roll, thereby make the more abundant contact screen cloth 12 of grit, realize better screening effect, the grit that the granule is less falls into the sieve case 11 of next stage and sieves once more, from this realize sieving step by step of grit, carry out automatic feeding through transport mechanism here, avoided artifical use spade to carry out the material loading, the manpower is saved, and the work efficiency is improved.

Compared with the prior art, this grit multi-stage screening device, realize the material loading through transport mechanism, realize the multi-stage screening of grit through screening mechanism, compare with current screening device, the device is through an output, can realize the operation of drive mechanism and screening mechanism, the energy has been saved, and the linkage through transport mechanism and screening mechanism, the online screening of grit has been realized, this linkage adopts pure mechanical structure simultaneously, electronic component's such as sensor use has been avoided, the stability and the life of device have been improved.

In light of the foregoing description of the preferred embodiment of the present invention, many modifications and variations will be apparent to those skilled in the art without departing from the spirit and scope of the invention. The technical scope of the present invention is not limited to the content of the specification, and must be determined according to the scope of the claims.

Claims

1. The multi-stage sand and stone screening device is characterized by comprising a base (1), a support rod (2), a cross rod (3), a conveying mechanism and a screening mechanism, wherein the support rod (2) is arranged at one end of the base (1), the cross rod (3) is arranged above the base (1) through the support rod (2), the conveying mechanism is arranged at one end, far away from the support rod (2), of the base (1), and the screening mechanism is arranged at one side, far away from the support rod (2), of a fixing plate (10);

the conveying mechanism comprises a driving assembly and a conveying assembly, the driving assembly comprises a motor (4) and a driving shaft (5), the motor (4) is horizontally arranged on the base (1), the driving shaft (5) is installed on the motor (4), the conveying assembly comprises a connecting unit and a conveying unit, the conveying unit comprises two rollers (6), two positioning shafts (7) and a conveying belt (8), one positioning shaft (7) is arranged at one end, close to the motor (4), of the base (1), the other positioning shaft (7) is arranged above the fixed plate (10), the two rollers (6) are arranged, the two rollers (6) are respectively sleeved on the two positioning shafts (7), the two rollers (6) are respectively in key connection with the two positioning shafts (7), and the two rollers (6) are in transmission connection through the conveying belt (8), the connecting unit comprises two rotating wheels (9), the two rotating wheels (9) are respectively sleeved on the driving shaft (5) and the positioning shaft (7), the two rotating wheels (9) are respectively in key connection with the driving shaft (5) and the positioning shaft (7), and the two rotating wheels (9) are in transmission connection through a belt;

screening mechanism includes screening subassembly, promotion subassembly and reply subassembly, screening subassembly includes fixed plate (10) and screening unit, fixed plate (10) have two, and two fixed plate (10) set up along the axis direction align to grid of branch (2), be equipped with the discharge gate on fixed plate (10), the screening unit has threely, and three screening unit sets up respectively on fixed plate (10) and base (1), the screening unit includes screening case (11) and screen cloth (12), screening case (11) set up on fixed plate (10), screening case (11) and fixed plate (10) sliding connection, screening case (11) bottom opening, screen cloth (12) set up the opening part in screening case (11) bottom, screen cloth (12) are just to setting up with the discharge gate, it includes carousel (13) to promote the subassembly, Bull stick (14), push pedal (15) and push rod (16), carousel (13) sets up on drive shaft (5), carousel (13) and drive shaft (5) fixed connection, carousel (13) and drive shaft (5) coaxial setting, bull stick (14) set up on carousel (13), bull stick (14) have two, and two bull sticks (14) set up respectively in the both sides of carousel (13), be equipped with the spout on base (1), the one end of push pedal (15) is located the spout, push pedal (15) and spout sliding connection, one of them bull stick (14) and push pedal (15) support and lean on, push rod (16) set up on push pedal (15), push rod (16) have threely, and three push rod (16) correspond the setting with three screening case (11) respectively, push rod (16) support with the one end of screening case (11) and lean on, reply the subassembly and include three reply unit, three reply unit corresponds the setting with three screening case (11) respectively, reply the subassembly and include depression bar (17), clamp plate (18) and spring (19), branch (2) are passed in depression bar (17), depression bar (17) and branch (2) sliding connection, clamp plate (18) set up the one end at depression bar (17), clamp plate (18) and screening case (11) keep away from the one end of push rod (16) and support and lean on, spring (19) cover is established on depression bar (17), spring (19) are located between clamp plate (18) and branch (2), the one end and the clamp plate (18) of spring (19) are connected, the other end and branch (2) of spring (19) are connected.

2. A multi-stage sand and gravel screening device as claimed in claim 1, wherein a bottom plate (20) is arranged at the opening at the bottom of the screening box (11), grooves are arranged on two sides of the opening of the screening box (11) below the screen (12) of the bottom plate (20), two ends of the bottom plate (20) are respectively arranged in the two grooves, and the bottom plate (20) is connected with the grooves in a sliding manner.

3. A multi-stage sand and stone screening device according to claim 1, wherein one end of the push plate (15) in the chute is provided with a slide block (21), the chute is provided with a strip-shaped groove, the slide block (21) is positioned in the strip-shaped groove, and the slide block (21) is connected with the strip-shaped groove in a sliding manner.

4. A sand multistage screening apparatus according to claim 3, wherein there are two slide blocks (21), two slide blocks (21) are respectively provided on both sides of the push plate (15), there are two strip-shaped grooves, and the two slide blocks (21) are respectively provided in the two strip-shaped grooves.

5. A sand multistage screening apparatus according to claim 4, wherein the cross-section of the slide block (21) is dovetail shaped and the strip groove is dovetail groove.

6. A sand multistage screening apparatus according to claim 1, wherein there are two said pressing rods (17), two said pressing rods (17) are respectively disposed on both sides of the pressing plate (18), both said pressing rods (17) pass through the supporting rod (2), there are two said springs (19), and two said springs (19) are respectively fitted over two said pressing rods (17).

7. The sand and stone multistage screening device according to claim 1, characterized in that the bottom of the screening box (11) is provided with two limiting blocks (22), the two limiting blocks (22) are respectively arranged at two sides of the screening box (11), the fixing plate (10) is provided with two limiting grooves, the two limiting blocks (22) are respectively positioned in the two limiting grooves, and the limiting blocks (22) are connected with the limiting grooves in a sliding manner.

8. A multi-stage sand and stone screening device according to claim 7, characterized in that the end of the limiting block (22) in the limiting groove is provided with a pulley, and the pulley is in rolling connection with the limiting groove.

9. A sand multistage screening apparatus according to claim 1, wherein baffles (23) are provided on said conveyor belt (8), said baffles (23) being a plurality, each baffle (23) being uniformly disposed.

10. A sand multi-stage screening apparatus as claimed in claim 1, wherein the end of the rotatable shaft (14) remote from the rotatable disc (13) is provided with rollers.